Effect of Artificial Graphite and Nickel Nitrate on the Microstructure and Properties of Carbon Blocks for Blast Furnace

Abstract

Improving thermal conductivity of carbon blocks is one of the most important developing trends for carbon blocks. In this work, artificial graphite and nickel nitrate catalyst were introduced into carbon blocks with an attempt to improve thermal conductivity of carbon blocks and their effect on microstructure and properties of carbon blocks were systematically studied by means of X ray diffraction (XRD), scanning electron microscopy (SEM) and laser thermal conductivity meter. The results revealed that artificial graphite possessed lower oxidation activation energy than electrically calcined anthracite, and thus, higher reactivity, which could accelerate the formation of SiC whiskers in carbon blocks and have a positive effect on thermal conductivity of carbon blocks. Moreover, it was interestingly noted that one dimensional nano-carbon was catalytically formed at 1000 °C and lots of Sialon phases were formed at 1400 °C when nickel nitrate catalyst was further added in carbon blocks containing artificial graphite. These in-situ ceramic phases formed in carbon blocks constructed high thermal conductive network and reduced the interface thermal resistance, thus improving the thermal conductivity of carbon blocks significantly.